Lets say that you have a Nikon 40mm F/2.8G DX "macro" lens. What would the results be if you installed an extension tube or a close up filter or even a Raynox DCR-250 converter on this lens ? Would this make your macro lens a "super macro" lens ? In other words could you get even greater than 1 to 1 shots. Or would these attachments result in the lens being so close to the subject that focusing would be impossible ?

Yes if you have a macro lens and install an extension tube or a conversion lens. You will go beyond 1:1 macro. But at the same time you will have way less working distance. And if you go the way of a conversion lens. It will magnified the flaws in a lower price conversion lenses.

I have shot super macro with a canon ef 100 2.8 macro lens with a canon 500D conversion lens. With the longer lens you will have a bit more working space.

To suppliment shoturtle's comments, in general, macro lenses are extraordinarily sharp, and since extension tubes don't have any optical elements of their own, the results you get when using a macro lens with extension tubes will be very much superior to the results you'll get with any close-up lenses or conversion lenses.

But while extension tubes (or any other add-on macro tool) will decrease the minimum focus distance, they will also greatly reduce the maximum focus distance, so focusing anywhere near infinity is out of the question.

This was a test with a true macro lens and a high end conversion lens. You can see the level of magnification you can get. But like I said you will have very little working distance. With the 100mm I felt like I was working with 50mm macro lens as it was almost on top of the subject.

Thanks everone for all of your replies to my question. I think that I now understand. Extension tubes on my Nikon 40mm macro lens would probably not work because I already have a very short working distance...about 1.3 inches for a 1 to 1 macro shot.

You may also consider using a teleconverter. You will obtain magnification increase proportional to the t/c ratio, and lose light in the same proportion, but, without a change in the lens to subject distance. The optical elements in the t/c may degrade the image quality somewhat, as well.

I would agree that with a 40mm lens you would almost have to go with a teleconverter to get more magnification. I've used a number of different things for macro and my preferences depend on what I'm shooting and whether I'm using a tripod or not. At the moment I think I prefer my teleconverter - it's a very high quality 1.7 TC. On the other hand, the one method I failed miserably with was using a poor quality 2X TC. That one was so bad I ended up taking the glass out of it and turning it into an extension tube (since I got the 2X TC for free, I was happy I ended up with something useful).

I once had a macro lens that had a matched adapter (essentially a dioper filter) that came with it to make it into a 1:1 lens. The optics on it were excellent so I think that using a high-quality add-on, like a Raynox, would give you good results, if you don't mind the shortened operating distance. I've thought about buying a Raynox 150 but haven't quite gotten around to it. The important thing (as was pointed out) is that you need a really sharp lens to start with.

Another thing you can do is to reverse a lens in front of another. I've done that - reversing either a 24mm or a 50mm lens in front of a 100 or 135mm lens (doesn't have to be a macro lens, just something really sharp). The 24mm was pretty difficult to use, preferred the results with the 50.

The one thing to keep in mind, no matter what method you use to get more than 1:1 magnification, is that your dof becomes very tiny. I can hand-hold 1:1 macro fairly easily, given enough light or an off-camera flash. I got so frustrated with the TC and the reversed 24mm that I gave up macro until I got some macro focusing rails for Christmas. That has made it much easier and less frustrating. It can be done without rails, but expect a lot of fiddling with a tripod to get the focus extactly right if using a tripod, or take lots of pictures and hope that you pushed the shutter at the exact moment when your body sway hit the focus point.